Surprisingly Good Apocalyptic Thriller - * Spoilers? *

This is stated to be a sci-fi thriller but the title is enough to suggest a more accurate definition. Yes, it may be what I usually define as a religious fantasy but, despite my general antipathy to the whole genre, I like this one.
It is well shot, well edited, well acted, the music is good and, most importantly, the writing is good too. The FX are anywhere from mediocre to genuinely good and they never ruin the scene (we are not talking Neil Breen or Birdemic or anything like that.) Once the survivors on the run start trying to explain events we get some talk of aliens and super-weapons and, inevitably, the Book of Revelation, but I think that is reasonable--in the face of utterly unreasonable events.